The court heard that the child now suffers from cerebral palsy affecting his whole body. He has a limited range of movement and will never be independently mobile.

Dobbie took the child, who cannot be named, to Victoria Hospital, Kirkcaldy, in June 2011 and receptionist Silvano Costagliola said she thought he was dead.

So too did staff nurse Jacqueline Keir, but when she moved his hand he was crying like he was in pain.

He had to be transferred to a specialist paediatric unit where consultant John Morrice said: "For an individual like this who looked so sick I would expect everyone to be available to help out."

"He was not behaving like a normal infant at this point. He was very irritable at times and at other times quite unresponsive," he said

The doctor noted bruising on the child's torso and small, pin prick bruises on other areas such as the top of the head.

He said the priority was to keep the baby alive, to resuscitate and stabilise him. He told the court: "He had life-threatening injuries."

The child was transferred to the Royal Hospital for Sick Children in Edinburgh where a CT scan was carried out. He was later taken to the Royal Hospital for Sick Children at Yorkhill in Glasgow to enable him to undergo neurosurgery.

He later went back to a Fife hospital but was returned to a specialist children's hospital because of continuing problems with seizures.

Detective Constable Kim Stuart said Dingwall-born Dobbie had told him that he had earlier fed the baby and changed his nappy and did not notice any marks on his body.

Jobless Dobbie said he had needed to go to the toilet and put the child in an upright position but when he returned found he had slipped onto his side and his head was resting on a plastic phone toy.

Dobbie said the child was crying and he picked him up and noticed a red mark. He said he was rocking the child.

He noticed the baby's eyes were rolling back. He took the baby to its mother and she told him to phone a taxi and take him to hospital.

But jurors heard that expert evidence pointed to the baby suffering violent shaking and direct impact to his head.

Defence solicitor advocate Gordon Martin said Dobbie had no record of violence. He said the offence appeared to involve "a single loss of control" after he snapped.